zeek/scripts/base/protocols/ntp/main.zeek
2019-05-29 09:37:55 -05:00

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module NTP;
@load ./consts
export {
redef enum Log::ID += { LOG };
type Info: record {
## Timestamp for when the event happened.
ts: time &log;
## Unique ID for the connection.
uid: string &log;
## The connection's 4-tuple of endpoint addresses/ports.
id: conn_id &log;
## The version of NTP
ver: count &log;
## The stratum (primary, secondary, etc.) of the server
stratum: count &log &optional;
## The precision of the system clock of the client
precision: interval &log &optional;
## The time at the client that the request was sent to the server
org_time: time &log &optional;
## The time at the server when the request was received
rec_time: time &log &optional;
## The time at the server when the reply was sent
xmt_time: time &log &optional;
## For stratum 0, 4 character string used for debugging
kiss_code: string &log &optional;
## For stratum 1, ID assigned to the clock by IANA
ref_id: string &log &optional;
## The IP of the server's reference clock
ref_clock: addr &log &optional;
};
## Event that can be handled to access the NTP record as it is sent on
## to the logging framework.
global log_ntp: event(rec: Info);
}
redef record connection += {
ntp: Info &optional;
};
const ports = { 123/udp };
redef likely_server_ports += { ports };
event zeek_init() &priority=5
{
Log::create_stream(NTP::LOG, [$columns=Info, $ev=log_ntp, $path="ntp"]);
Analyzer::register_for_ports(Analyzer::ANALYZER_NTP, ports);
}
event ntp_message(c: connection, is_orig: bool, msg: NTP::Message) &priority=5
{
# Record initialization
local info: Info;
if ( c?$ntp )
info = c$ntp;
else
{
info$ts = network_time();
info$uid = c$uid;
info$id = c$id;
info$ver = msg$version;
}
# From the request, we get the desired precision
if ( is_orig )
{
info$precision = msg$precision;
c$ntp = info;
return;
}
# From the response, we fill out most of the rest of the fields.
info$stratum = msg$stratum;
info$org_time = msg$org_time;
info$rec_time = msg$rec_time;
info$xmt_time = msg$xmt_time;
# Stratum 1 has the textual reference ID
if ( msg$stratum == 1 )
info$ref_id = gsub(msg$ref_id, /\x00*/, "");
# Higher stratums using IPv4 have the address of the reference server.
if ( msg$stratum > 1 )
{
if ( is_v4_addr(c$id$orig_h) )
info$ref_clock = msg$ref_addr;
}
c$ntp = info;
}
event ntp_message(c: connection, is_orig: bool, msg: NTP::Message) &priority=-5
{
if ( ! is_orig )
{
Log::write(NTP::LOG, c$ntp);
delete c$ntp;
}
}
event connection_state_remove(c: connection) &priority=-5
{
if ( c?$ntp )
Log::write(NTP::LOG, c$ntp);
}
event ntp_mode6_message(c: connection, is_orig: bool, opcode: count)
{
print "Mode 6", opcode;
}
event ntp_mode7_message(c: connection, is_orig: bool, opcode: count)
{
print "Mode 7", opcode;
}